Analog Devices Inc./Maxim Integrated MAX6323AUT29+T

Overview

MAX6323AUT29+T from Maxim Integrated is a push-pull-output microprocessor supervisory circuit with windowed (min/max) watchdog, 2.93V ±2.5% reset threshold, 100ms minimum reset timeout, and operation from 1.2V to 5.5V supply. It monitors VCC and WDI timing in automotive engine control units to detect firmware hangs or clock faults before system failure.

For engineers reviewing the MAX6323AUT29+T datasheet, MAX6323AUT29+T pinout, MAX6323AUT29+T application, or MAX6323AUT29+T equivalent, key selection criteria include guaranteed RESET validity down to VCC = +1.2V, factory-trimmed slow watchdog timeout of 300ms (C-window), fast timeout of 15ms, debounced MR input, and AEC-Q100-compatible SOT23-6 packaging for under-hood reliability.

Technical Context

The MAX6323AUT29+T implements a dual-threshold watchdog that triggers WDPO on either early (faster than 15ms) or late (slower than 300ms) falling edges at WDI - not just missing pulses. Its internal comparator guarantees reset assertion when VCC drops below 2.93V (±2.5%), with hysteresis and noise immunity via 500pF VCC bypassing.

RESET is push-pull active-low with VOH ≥ 0.8×VCC and VOL ≤ 0.4V at 1.2mA sink, enabling direct interface to 1.8V–5V µP reset inputs without external pullups. WDPO is open-drain, pulsed low for 1ms upon fault detection, and remains inactive while RESET is asserted.

Key Specifications

Pinout & Package

MAX6323AUT29+T is housed in a 6-pin SOT23 package (package code U6+1A), with 1.3mm × 2.1mm footprint, 0.95mm height, and JEDEC-compliant thermal resistance (θJA = 115°C/W on multilayer board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6324AUT29+T, the MAX6323AUT29+T provides immediate µP reset drive without pullup dependency; versus TPS3808G33DBVR, it delivers critical windowed watchdog functionality essential for ISO 26262 ASIL-B compliance in automotive control systems.

Availability

MAX6323AUT29+T is available at Aetrix Electronics and suitable for automotive engine control units, industrial programmable logic controllers, and medical infusion pump controllers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6323AUT29+T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated, now part of Analog Devices, designs precision analog and mixed-signal ICs for demanding industrial, automotive, and medical applications.

The MAX6323/MAX6324 family was engineered specifically for functional safety-critical µP supervision, integrating windowed watchdogs and guaranteed low-voltage reset to meet AEC-Q100 and IEC 61508 requirements.

FAQ

What is the exact reset threshold voltage of MAX6323AUT29+T and how is it trimmed?

The MAX6323AUT29+T has a nominal reset threshold of 2.93V with ±2.5% accuracy over -40°C to +125°C. This value is achieved through factory laser trimming of on-chip resistors, as confirmed in the Electrical Characteristics table (VTH = 2.85V to 3.00V). No external calibration is required, and the tolerance is guaranteed across the full operating temperature range - critical for consistent behavior in automotive under-hood environments.

Does MAX6323AUT29+T support windowed watchdog functionality, and what are its timeout values?

Yes, MAX6323AUT29+T implements true min/max (windowed) watchdog functionality. For the "C" suffix, the fast timeout is 15ms (minimum interval between WDI falling edges), and the slow timeout is 300ms (maximum allowable interval). These values are factory-laser-trimmed and do not require external components - enabling precise detection of both runaway loops and stalled execution in real-time µP systems.

Can MAX6323AUT29+T operate reliably during deep brownout conditions?

Yes, MAX6323AUT29+T guarantees valid RESET output down to VCC = +1.2V, as explicitly stated in the General Description and Electrical Characteristics. Below this voltage, the RESET output becomes high-impedance, but above it - including during gradual brownout - the push-pull driver maintains defined logic levels. This ensures µP reset integrity even as the monitored rail collapses, preventing undefined states in safety-critical applications.

What is the function of the WDPO pin on MAX6323AUT29+T, and how should it be used?

The WDPO (Watchdog Pulse Output) pin on MAX6323AUT29+T is an open-drain output that pulses low for 1ms upon detection of either a fast or slow watchdog fault. It remains inactive while RESET is asserted. To use WDPO, connect a pullup resistor (e.g., 10kΩ) to any supply ≤+6V. WDPO provides an independent fault signal - useful for logging, triggering NMI, or initiating WDPO-to-MR loopback for guaranteed 100ms reset assertion.

Is MAX6323AUT29+T qualified for automotive applications, and what evidence supports this?

While MAX6323AUT29+T itself is not marked with /V (AEC-Q100 qualification suffix), it shares identical die, SOT23-6 packaging, -40°C to +125°C operating range, and electrical specifications with AEC-Q100-qualified variants like MAX6324HUT44/V+T. Its design intent, thermal performance (θJA = 115°C/W), and guaranteed parameters across the full automotive temperature range confirm suitability for non-safety-critical automotive subsystems - though formal AEC-Q100 certification applies only to /V-suffixed versions.